1. Field of the Invention
The present invention relates to the field of medical devices. More specifically, the invention relates to a pessary device and method that uses a non-circular shape to prevent rotation within the vagina, resilient portions to define the fold axis, and other features to improve the performance of the pessary.
One type of pessary commonly used today is the ring pessary. A typical ring pessary has a toroidal outer ring, that is circular in cross section. In addition, some ring pessaries include an inner membrane support attached to the toroidal outer ring. Thus, the membrane support fills the circular inner cavity defined by the toroidal outer ring and acts as a sling that helps to support various degrees of prolapse. Generally, the membrane support includes passageways therethrough to facilitate the flow of bodily fluids through the pessary.
A ring type pessary is inserted into the vaginal cavity. Typically, the ring pessary is constructed of a resilient, though fairly rigid, biocompatible material such as medical grade silicone that permits the pessary to be folded for insertion.
To ensure that the pessary remains in position and does not become folded and, then, move out of position or exit the vagina, the pessary is designed to fold along a particular axis. In a typical ring pessary, the fold axis is created by forming the outer ring of the pessary around two semicircular, rigid wires or rods. The ends of the semicircular wires meet (without necessarily touching) at the fold axis and effectively prevent folding of the pessary in any other direction. In addition, many pessaries include a pair of small indentations formed in the inner portion of the toroidal outer ring at the fold axis. The indentations facilitate folding at the fold axis and help to identify the fold axis to the user.
Once inserted, the pessary is rotated ninety degrees to ensure that it is fully unfolded and properly positioned and to position the fold axis 20 lateral to the insertion/extraction direction. With the fold axis positioned at a ninety degree angle to the insertion/extraction direction, the pessary cannot fold and move out of position during normal use.
However, one problem associated with standard ring pessaries is that normal activity can cause the pessary to rotate in the vagina. When the pessary inadvertently rotates so that the fold axis is aligned with the insertion/extraction direction, the pessary may become inadvertently folded and move out of position. Such a result is undesirable because the ring pessary no longer provides adequate support and has a tendency to fold and fall out.
Thus, despite the use of the prior art features, there remains a need for a pessary that does not inadvertently rotate within the vagina during normal use.
Another problem associated with standard ring pessaries is associated with the use of the rigid wires to define the fold axis. Occasionally, the silicone, or other material, surrounding the wire will tear exposing the wire. The tear often occurs at the fold axis at the end of the wire. Therefore, a tear of the pessary often exposes the user of the pessary to a bare, rigid wire in a very sensitive area for the user which can result in injury.
Therefore, there is a need for a pessary that eliminates the rigid wire, but maintains the fold axis feature.
2. Description of Related Art
A pessary which utilizes stainless steel or a hard plastic material for the rigid inserts to define the fold axis is shown in U. S. Patent No. 5,771,899 (Martelly et al.) A sling support is also shown positioned at an acute angle to the axis of the main ring.